Tertiary Petroleum System along Sorong Fault in the Bird Head of Papua to South of Halmahera Area, I

Tertiary Petroleum System along Sorong Fault in the Bird Head of Papua to South of Halmahera Area, Indonesia
Surjono, S.S^1,2 , Toha, B² & Winardi, S²

^{1, 2} Geological Engineering Department, Faculty of Engineering, Gadjah Mada University

Jalan Grafika No.2, Yogyakarta, 55281, INDONESIA

¹(sugengssurjono@gmail.com)

Abstract

Sorong Fault occurred in the northern part of Papua Island westward to the eastern part of Sulawesi Island is the boundary of Australian Continental and Pacific Oceanic Crusts. Close to the fault zone, there is the Salawati Basin that proofed as prolific tertiary basin in the eastern Indonesia developed among the Paleozoic and Mesozoic Basins. Sorong Fault which have initiated in the Late Miocene deformed northern part of Papua westward to form transtensional basin including Salawati. Several explorations in Sorong Fault zones have been done following the successful of Salawati which their petroleum system rely on the Miocene Carbonate reservoir of Kais Formation with the younger Klasafet shale as the sources rocks. Juxtaposed stratigraphic position is the main petroleum play for this basin.

This study elaborated gravity, seismic, well and surface geological data to reveal petroleum system developed in the study area. Due to limitation of well data as reference, sub surface geology was interpreted through seismic stratigraphy methods. This study indicates that tertiary sediments in the Sorong Fault zone mainly were deposited directly over the Paleozoic basement. However the Mesozoic sediments have not existed in this area.  Identifying basement type is important key to know the possibility for the productive source rocks. In the Bird Head area, the occurrence of petroleum play is mainly interpreted by existence of the Miocene carbonate build up developed on the succession directly overlying basement. To the Halmahera area, carbonate rock developed in association with volcanic rocks in the Late Eocene to Early Oligocene times. Further research in this area will be more focused on identifying the presence of Middle Miocene carbonate source rocks in the eastern area and the intraformational organic rich of Early Miocene shale.
Acknowledgement

Authors acknowledge to the Ditjen Migas Indonesia for presenting this paper. Many thanks addressed to all team member of Joint Study in Bird Head, Obi-Bacan and Halmahera areas.